Wire-tinning apparatus



May 28, 1968 N, QRBAN ET AL WIRE-TINNING AlPARATUS 5 Sheets-Sheet 1 Filed Jan. 9, 1963 May 28, 1968 QRBAN ET AL 3,385,259

WIRE-TINNING APPARATUS Filed Jan. 9, 1963 5 Sheets-Sheet 2 May 28, 1968 N. ORBAN ET L WIRE-TINNING APPARATUS Filed Jan. 9, 1963 5 Sheets-Sheet 5 86 F g. 5 w;

May 28, 1968 N. ORBAN ET AL WIRE-TINNING APPARATUS 5 Sheets-Sheet 4 Filed Jan. 9, 1963 rlll IIIIIIIIIIIIL May 28, 1968 ORBAN ET AL 3,385,259

WIRE-TINNING APPARATUS Filed Jan. 9, 1963 5 Sheets$heet 5 Fig. 8

United States Patent 0 3,385,259 WHRETINNHNG APPARATUS Nicolas Urban and Jean Gonguet, Paris, France, as-

signors to Socit Anonyrne Geoffrey-Delete, Paris, France Filed'Jan. 9, 1963, Ser. No. 250,261 Elaims priority, appiication France, Jan. 10, 1962, 834,361 4 Claims. (Cl. 118-63) This invention relates to apparatus for tinning wire, especially copper wire, by immersion in a bath of molten tin. Our main objects are to provide such apparatus whereby the wire can be tinned eificiently and reliably at speeds higher than those heretofore considered practicable, and specifically to permit the timing to proceed at a rate equal to the rate at which the wire is drawn, thereby to provide a combined wire-drawing and tinning installation through which the wire can be progressively and uniformly passed in a continuous wiredrawing and -tinn=ing process.

In conventi nal copper Wire tinning installations using the hot dipping method, the wire is usually delivered to the installation already in an annealed state, from a wiredrawing and -annealing plant. In the timing installation, the annealed wire is subjected to one or more surface processing steps, which may typically include degreasing, scouring, and fluxing through some of these steps may be combined with others or omitted altogether. The surfaceprocessed wire is then passed through a bath of molten tin, thence through a cooling stage in which the tin coating is allowed to solidify, and is finally taken up at a receiver station.

it would be highly desirable in many instances to subject the wire to the surface-processing and tinning steps continuously as the wire emerges from the wire drawing unit, thereby providing a single, combined wire-drawing and -tinning plant which would possess self-evident economic advantages. Previ us attempts to reach this result, however, have generally failed commercially, since it has not been found possible in practice to perform the hot tinning operation at a rate consistent with the current high rates of wire drawing without exposing the wire to breakage and/or unsatisfactory tin coating results.

It is an essential object of this invention to attain the result just specified and provide a combined wire-drawing and -tinning installation that will be practically and commercially successful from all p ints of view.

Important further objects are to provide wire-tinning apparatus embodying improved means for controlling the I conditions of treatment of the wire within the bath of m lten tin, including the guiding of the wire through the bath, immersion depth control, wiping ofi of excess molten tin from the wire surface, variations in wire feed rate and tension, oxidation control, and other factors f und important in the successful performance of a high-speed tinning process. Further specific objects will appear as the disclosure proceeds.

According to an important aspect of the invention, it has been found that one of the chief reasons that has limited the tolerable rate of feed of the Wire through the bath of molten tin has been the fact that the guide means used for guiding the wire into and out of the bath have been generally provided in the form of a rotatable grooved pulley around which the wire was trained so as to rotate the pulley at a rate proportional to the wire feed vel city.

This results in agitation and turbulence in the bath of molten tin, promoting oxidation of the tin especially at high feed rates. To avoid this, it has been prop sed to increase the depth of the bath, but this increases heat losses and installation as well as maintenance costs.

In accordance with an aspect of the invention, the above Patented May 28, 1968 dii'llculty is avoided by providing a relatively stationary guide member for guiding the wire into and out of the tinning bath, in the form of a grooved pulley or sector made of a suitable material to withstand the temperature of the bath of molten tin, and immersed at an appropriate preferably controllable depth bel w the free surface of the bath.

Other aspects and features of the invention will appear hereinafter.

Exemplary embodiments of the invention as applied to a combined, continuous wire-drawing and -tinning installati on will now be described for purposes of illustration but not of limitation with reference to the accompanying drawings, wherein:

FIGURE 1 is a general View, in simplified elevation, of one form of combined wire-drawing and -tinning installation according to this invention;

FIGURE 2 is a somewhat more detailed view of one of the surface-processing tanks shown in FIGURE 1, on a larger scale;

FIGURE 3 is a view of the tank of FIGURE 2, in sectional elevation on a vertical plane normal to the plane of that figure;

FIGURE 4 is a view similar to FIGURE 2 illustrating a somewhat different type of processing tank unit also included in the installation of FIGURE 1;

FIGURE 5 is a detailed view of the tinning unit included in the installation of FIGURE 1, in the operative position of the components;

FIGURE 6 is a similar view with the parts in raised position for threading the wire through the tinning unit;

FIGURE 7 illustrates in a manner similar to FIGURE 1 a modified layout of the combined wire-drawing and -tinniug plant; and

FIGURE 8 illustrates a modification of part of FIG- URE 1.

Referring especially to FIGURE 1, the improved wiredrawing and -tinning plant shown comprises a Wire drawing unit 1, followed by an annealing unit or furnace 2, both of which may be of conventional types. The wire 4 is fed continuously from the wire drawing unit 1 through the furnace 2 by means of conventional drive apparatus including a motor indicated at 3, and is then passed successively through a degreasing tank 5, a scouring tank 6, a fiuxing tank 7, a tinning unit 8 and a cooling tank 18, whence it is taken up in a suitable collector unit 11, such as a reel driven by another motor (not shown) synchronized with motor 3.

The degreasing tank 5, scouring tank i; and cooling tank it may all be of a substantially similar construction which is illustrated in FIGURE 2 and FIGURE 3. Each of these tank units is seen to comprise three main sections: a lower tank section or sump 51 adapted to contain a body of suitable treating liquid, an upper section 52 topped by a removable cover 52a, and a side chamber 53 provided with a removable top cover 530. The upper section or body 52 of the tank has a sealed horizontal box-like casing 54 extending partly through its upper part and having slots 54a and 54b formed in its end walls through which the wire 4 is threaded. A supply of the treating liquid from reservoir or sump 51 is led into the casing 54 through a bottom inlet 54c thereof connected by a line 56 to a motor-driven pump unit 55 drawing liquid out of the sump 51. The excess liquid flows out from casing 54 through the end slots 54a and 54b back into the sump 51.

The side chamber 53 which extends from a side Wall of the upper or body section 52 has a set of e.g. three grooved pulleys 57a, 57b, 57c rotatably mounted in it, with the wire 4 issuing after treatment from out of the elongated casing 54 passing in the grooves between said pulleys prior to emerging out of the tank unit. The end pulleys 57a and 570 are preferably adjusted so that the bottom of their respective peripheral grooves is substantially tangent to the axis of the wire. The middle pulley 57b is adjustable to control the pressure applied to the wire. The set of pulleys 57a, b and c are driven in rotation by the wire 4 at a high angular velocity, and the resulting centrifugal force developed at the periphery of the pulleys in the areas engaging the wire acts to discharge the excess liquid entrained with the wire against the walls of the chamber 53. Defiecting bafiles 58a, 58b and 580 are provided to minimize the impingement of the projected liquid against the adjacent pulleys. The liquid thus discharged fiows back into the sump 51 over the sloping bottom wall of chamber 53.

The fiuxing tank unit 7, shown in FIGURE 4, is constructed generally similarly to the tank units 5, 6 and 10 just described with reference to FIGURES 2-3. In transverse section the arrangement is identical and has not therefore been shown anew. The fluxing tank 7 comprises a lower sump 71 containing treating liquid, an upper body section 72 with a removable top 72a and a side chamber 73 with removable top 7311. Extending in the upper part of upper section 72 is an elongated box-like casing 74 through which the wire 4 is passed through end slots 74;: and 74b, and is supplied with liquid from the sump through a lower inlet 74c by a pumping unit similar to pumping unit 55 in FIGURE 3, and by Way of a line 76. The liquid in excess is discharged through slots 72a and 74b and flows back into sump 71.

The side chamber 73 in this instance comprises a set of only two grooved pulleys 77a and 77b so arranged that the wire 4 is subjected to two changes in its direction of feed before issuing out of the tank unit 7. In this case also the pulleys are driven in rapid rotation by the Wire whereby centrifugal force discharges the liquid from the wire with which it was entrained. Baffles 78a, 78b and 780 shield the pulleys from impact by the discharged liquid, which flows back into sump 71 over the sloping bottom wall of chamber 73. Preferably, a pressure air jet 79 is mounted near the exit point of wire 4 from side chamber 73 to discharge a stream of compressed air over the wire in a direction counter to that of wire displacement, in order to blow back into the chamber any remnants of entrained liquid. The tinning unit 8, shown in FIGURES 5 and 6, comprises a tank of a type generally similar to that conventionally used for similar purposes,

including the usual heating and thermal insulation means not shown. According to the invention, the tinning tank has associated with it relatively stationary wire-guide member and a pair of devices generally designated 81 and 91 respectively, which jointly serve to control the treatment of the wire in the bath of molten tin contained in tank 8.

Whereas in conventional wire-tinning baths, the means for guiding the wire into and out of the bath have generally comprised a rotatable grooved pulley, according to the present invention there is provided a relatively stationary grooved wire guide member, associated with means for controlling the depth thereof below the free surface of the bath. Device 81 comprises a supporting frame 81a secured by suitable means over the top of the tank, and carrying a transversely extending shaft 82 about which is pivoted a vertical plate 81b. Pivoted to two vertically spaced points of plate 81b at 85a and 85b are two parallel lever arms having their remote ends pivoted at 84a and 84b to a further vertical plate 81d to provide a parallel linkage system therewith. Plate 81d is provided with a downward extenison which dips into the bath of molten tin in tank 8 and has secured to its bottom end within the tin bath a relatively stationary wire guide member shown in the form of a grooved pulley 88 non-rotatably secured to a side of the plate extension. Instead of a complete pulley as shown the wire guide may be provided in the form of a grooved sector of say 180 arcuate extent. The wire guide 88 is made of a suitable material able to withstand the temperature of the tinning bath, e.g. steel or a sintered ceramic mass. The wire 4 is slidably engaged through the groove of wire guide 88, and in operation the sliding displacement of the wire through the groove is found to proceed smoothly and satisfactorily, assisted by the lubricating action of the molten tin.

The plate 81b has an arm projecting from it beyond its pivot 82 and carrying a counterweight 81c, the angular displacement of which is restricted to an arc of somewhat more than 90 by a pair of spaced stops 81c and 81 projecting from a side of plate 81b and engageable with opposite sides of the counterweight carrying arm. The upper lever arm 83a of the parallel linkage system described above has an extension arm 86a projecting upwardly at an angle from it and serving as an actuating lever whereby the lever arm 83a and hence, with it, the lower lever arm 83b can be rotated about their pivots 85a and 85b relatively to plate 81b, thereby to modify the vertical position of plate 810 and appended parts with respect to the bath as later described. A ratchet sector 87 secured to the upper part of plate 81b is engageable by a pawl, not shown, actuated by means of a trigger 86 mounted near the top of the actuating lever 86a in order to determine the setting of the plate 81d relative to plate 81b during the movement just described.

Also supported on the lower extension of plate 81d vertically above the wire guide pulley 88 so as to be engaged by the wire as it emerges out of the pulley groove is a wiper member 89 such as a calibrated wiper die, which is loosely positioned within a mounting cage so as to be freely movable a limited amount in all directions. The wiper device 89 should be so positioned as to have its lower, wire-inlet orifice at all times positioned below the free surface of the tin bath and its outlet orifice above that surface. Due to this arrangement the wiper die is at all times maintained substantially at the temperature of the molten tin, yet the wire on emerging from the die 89 is above the free surface of the tin and its surface can therefore be effectively wiped clean of excess liquid tin. To control the immersion depth of the wire, and also maintain the precise relationship between the vertical position of the wiper device or die 89 and the free surface of the tinning bath as the tinning operation proceeds, actuating lever 86a is operated continuously or at intervals, manually or automatically, to alter the vertical position of plate 81d and hence wiper die 89 in accordance with variations in bath depth. Thus as the molten tin is gradually depleted, lever 86a is gradually moved counterclockwise (in FIGURE 5) with the pawl being stepped leftwards over the ratchet teeth of sector 87 to lower the plate 81d and hence guide pulley 88 and wiper die 89 correspondingly, thereby maintaining the guide pulley at constant depth and the wiper at the relative depth described above, i.e. with its inlet orifice beneath the bath surface and its outlet orifice above the surface.

It will be observed that the common supporting means described above for the guiding device 88 and wiping device 89, are capable of two different types of movement relative to the tank: first a bodily swinging movement about shaft 82 whereby said devices remain at substantially constant depth despite unavoidable variations in wire feed rate and tension, and secondly, depth control adjustment by means of lever 86a independently of said constant depth movements.

The wire 4 after passing through the wiper die 89 and emerging out of the tinning bath, in a generally vertical direction as here shown, in seen in FIGURE 5 to pass somewhat to the right of the center of shaft 82 about which plate 81b is pivoted to the stationary supporting frame 81a.

The device 91 which serves as an inlet device for the wire 4 into the tinning bath comprises a metal sheet bent to provide a flanged inverted channel or tunnel supported at its upper end from a bracket 92 pivoted about a transverse shaft 93 on fixed support 94. The lower end of channel 91 which is normally immersed in the tin bath is extended by an extension rod 95 the free end of which rests freely upon a supporting lug 90 projecting from a side of plate 81d adjacent guide pulley 88 in a position such that the wire 4 as it issues out of the channel 91 enters smoothly into the groove of guide pulley 88. This arrangement ensures that in case of variations in feed rate and tension of the wire as may occur during the process, resulting in bodily rotation of the Wire guide and wiping structure about pivot 82, such rotation will not interfere with the proper feed of the wire to the groove of the guide pulley, since the channel member 91 will undergo corresponding angular displacements due to the free support of its extension rod 95 on the fulcrum 90.

Connecting with the channel member 91 intermediate its length is a gas discharge pipe 96 through which an inert gas is delivered during operation, the gas being discharged out of the channel through the inlet orifice for wire 4. Thus, the wire 4 prior to entering the tin bath is continuously swept by an inert gas preventing objectionable oxidation and formation of tin oxide slag on the bath surface.

To thread a wire through the tinning apparatus described on commencing a tinning process, the entire apparatus is moved to the piston shown in FIGURE 6. That is, the wire-input member 91 is rotated counterclockwise about its pivot 93 to the upper position shown, in which it may be temporarily retained :by any suitable hooking arrangement not shown. The variable-depth guide and wiper device 81 is bodily rotated about the pivot 82 until the counterweight arm 81c engages the rest stop 81 It will be seen that in this position of the parts a straight horizontal path is provided for the wire 4 extending between the ends of the side flanges of channel member 91, through the groove in guide pulley 88 tangentially to the bottom of the groove, and through wiper die 89 and below pivot shaft 82. In this position therefore the wire can easily be threaded through this straight-line path, after which the variable-depth guide and wiper assembly 81 is rotated back to its operative position (FIGURE 5), and the channel member 91 is then eased in turn to bring its extension arm 95 to rest on the fulcrum 90 adjacent the guide pulley. Lever 86a is adjusted to bring the wiper device 89 to the exact requisite depth relative to the bath surface, and the tinning process can commence with inert gas being delivered through pipe 96 into the inlet channel 91.

Returning to FIGURES 5 and 1, the wire 4 issuing vertically out of the tin bath and wiper die 89, is first made to traverse a comparatively long run through the atmosphere to pre-cool the coat of tin on its surface and cause it to solidify sufficiently to allow the wire being safely passed around an overhead guide pulley 96 supported from a gallows 97. The length of this pre-cooling run will of course depend on conditions, including especially the rate of feed of the wire, but may be of the order of 4 meters. Gallows 97 is accordingly preferably made collapsible to facilitate threading the wire round pulley 96. The wire then is shown as running downwards at an angle to a further guide pulley 98 from which it passes into a cooling tank unit 10, which may conveniently be constructed similarly to each of the tank units 5 and 6 previously described. From the cooling tank the tinned wire is passed over an output guide pulley 9 into the take-up reeling device 11.

In the partial modification of the above described plant which is illustrated in FIGURE 8, applicable in cases where the pro-cooling of the tin-coated wire by a free run through atmosphere would require an inordinately long distance, the wire may be withdrawn from the tinning bath 8 at an upward angle, as shown, and passed through a suitable slot into a pre-cooling tank 100 through which a cooling liquid is circulated. Thereafter the wire is directed over guide pulley 96 and the remainder of the installation may be similar to that shown in FIG- URE 1, except that the cooling tank 10 may possibly be omitted.

It will be understood that in the wire-drawing and tinning plant illustrated schematically in FIGURE 1 the speed of the input drive motor 3 serving to feed the wire 4 through the wire drawing unit 1 and succeeding units of the series, should be synchronized with the speed of the take-up motor operating the receiver unit or reel 11. Considerable care should be exerted during the starting period of a tinning process, especially when dealing with fine-gauge wire, to avoid the danger of breaking the wire, and for this purpose the synchronous drives of both motors should be controlled in a highly progressive manner. Thus, the input motor 3 may advantageously be a slip motor or provided with a suitable slip coupling of any suitable type, and any suitable synchronizing or slaving means may be used to synchronize the rotations of the input and output motors.

In the modified installation shown in FIGURE 7, the layout is designed to save floor space and provide for taking up the tinned wire at a station adjoining the wire drawing unit, which may be convenient in many cases. This lay-out simultaneously permits the use of a cooling unit which is frequently incorporated in conventional annealing furnaces. In this arrangement, it will be noted that the various units of the plant, readily identifiable in that they are designated by the same reference numerals as the respectively corresponding units of FIG- URE 1, are so laid out that the wire 4 is passed from the annealing unit 2 towards degreasing tank 5 positioned at the remote end of the chain of apparatus units, then back in reverse through degreasing tank 5, scouring and fiuxing tank 7 (herein shown combined merely for illustrative purposes), through the tinning apparatus 8 similar to that described with reference to FIGURES 5 and 6, then up over guide pulley 96 into a cooling tank provided in the lower part of annealing furnace 2, to be finally taken up at receiver station 11 directly associated with the wire-drawing unit 1.

It will be evident that a great variety of other modifications than those shown and described may be introduced into the combined wire-drawing and tinning plant of the invention, as by combining certain of the processing steps with one another, altering the path of travel of the wire between the respective stages, and modifying the mechanical details of the tinning apparatus proper. Automatic depth control means for the wire guide pulley 88 and wiper 89 can easily be designed to replace or combine with the manual means shown. All such variations are to be considered as lying within the scope of the invention.

What we claim is:

1. In wire-tinning plant, the combination of a tank containing a bath of molten tin; wire-guide means within the bath having an arcuate guide groove engageable by the wire for guiding same down into the .bath and up out of the bath; a first support member swingable about a horizontal axis above the bath surface; a second support member having said guide means attached thereto and pivotally connected to said first member by parallel linkage means for up and down displacement relative to said first member, and control means for displacing said second member relative to said first member independently of the swinging movements of said first member to control the depth of immersion of said guide means within the bath.

2. In wire-tinning plant, the combination of a tank containing a bath of molten tin; a wire guide in the bath having an arcuate guide groove engageable by the wire for guiding same over an upgoing path out of the bath; a first support member swingable about a horizontal axis above the bath surface; a second support member having said guide attached thereto and pivotally connected to said first member for up and down displacement relative thereto independently of said swinging movement; an elongated inlet wire guide member having means pivoting the upper end thereof about a horizontal axis parallel to said first axis above the tank surface, said inlet member extending at a downward angle into the bath and towards said wire guide and being engageable by said wire for guiding the wire toward said guide groove; and fulcrum means freely supporting a lower end of said inlet guide member on said second support member adjacent said grooved guide member whereby to permit said inlet guide member to move freely about its upper end pivoting means in response to said swinging displacements of said first support member and in response to up and down displacements of said second support member.

3. Plant as claimed in claim 2, including a gas discharge outlet connected with said elongated inlet wire guide member for delivering a non-oxidizing gas thereinto and around said wire on its way into said bath.

4. Plant as claimed in claim 2, including means for bodily swinging said first and second support members about said first horizontal axis and said inlet member about said second horizontal axis to place said members into respective positions above the bath surface in which a substantially straight'line horizontal path is defined for threading said wire through said inlet member and guide means.

References Cited UNITED STATES PATENTS 345,382 7/1886 Hill 1l8-420 470,000 3/1892 Hopkins ll8420 X 767,422 8/1904 Nicholls 118420 X 1,235,860 8/1917 Valois 118-420 1,289,379 12/1918 Brumfield l18420 1,512,371 10/1924 Sommer 118420 X 1,765,743 6/1930 Sommer 118-420 X 1,843,078 1/1932 Berger 1l8420 X 1,940,748 12/1933 Gwaltney 118420 X 2,068,352 1/1937 Schlacks 118420 X 2,884,893 5/1959 Kabelitz 118-419 X MORRIS KAPLAN, Primary Examiner. 

1. IN WIRE-TINNING PLANT, THE COMBINATION OF A TANK CONTAINING A BATH OF MOLTEN TIN; WIRE-GUIDE MEANS WITHIN THE BATH HAVING AN ARCUATE GUIDE GROOVE ENGAGEABLE BY THE WIRE FOR GUIDING SAME DOWN INTO THE BATH AND UP OUT OF THE BATH; A FIRST SUPPORT MEMBER SWINGABLE ABOUT A HORIZONTAL AXIS ABOVE THE BATH SURFACE; A SECOND SUPPORT MEMBER HAVING SAID GUIDE MEANS ATTACHED THERETO AND PIVOTALLY CONNECTED TO SAID FIRST MEMBER BY PARALLEL LINKAGE MEANS FOR UP AND DOWN DISPLACEMENT RELATIVE TO SAID FIRST MEMBER, AND CONTROL MEANS FOR DISPLACING SAID SECOND MEMBER RELATIVE TO SAID FIRST MEMBER INDEPENDENTLY OF THE SWINGING MOVEMENTS OF SAID FIRST MEMBER TO CONTROL THE DEPTH OF IMMERSION OF SAID GUIDE MEANS WITHIN THE BATH. 